Stefan Ruvčeski

LakoZakazi — Novi Sad, Serbia — Founder & CTO

November 2023 - Present

Led the development and launch of lakozakazi.rs, a versatile appointment booking platform designed to serve a diverse range of service providers, including hairdressers, lawyers, and dentists. I managed a multidisciplinary team, overseeing all aspects of development, sales strategies, and project execution. I was responsible for designing and implementing the platform’s core logic and user-centric functionalities, ensuring a seamless and intuitive booking experience for both service providers and their clients. Additionally, I played a key role in product design, aligning the platform's features with market demands and user feedback. Beyond technical responsibilities, I contributed to strategic planning and sales efforts, ensuring the platform’s successful adoption and growth. This end-to-end involvement honed my leadership, project management, and full-stack development skills, demonstrating my ability to drive a project from concept to completion with measurable results.

Mistho GmbH — Berlin, Germany (Remote) — Senior Backend Engineer

August 2022 - August 2023

Specialized in developing event-driven backend APIs for real-time income and employment verification, which integrated data from multiple global financial sources. Architected microservices using Node.js and Kafka, enabling the system to handle thousands of requests per second with minimal latency. Focused on improving system performance by reducing API response times by 40%, ensuring that the verification process remained fast and reliable even under heavy load. Implemented rigorous security measures, adhering to GDPR and ISO 27001 standards for encryption and data protection, resulting in zero security breaches during my tenure. Worked on optimizing the microservices architecture to enhance scalability and fault tolerance, allowing the platform to dynamically scale based on demand.

GitHub Inc. — Remote — Senior Software Engineer - Part Time Vendor

July 2022 - July 2024

Led the development and optimization of the Action Runner Controller and Runner components for GitHub Actions, supporting millions of users daily in automating their CI/CD pipelines. The project involved enhancing the efficiency of the Runner, which executes user-defined workflows, by optimizing its core processes. Focused on improving scalability by ensuring the system could handle a growing number of concurrent workflows across diverse platforms, such as Linux, Windows, and macOS. Leveraged Node.js, Go, and .NET to build and maintain features that increased the reliability and fault tolerance of the system. Introduced performance improvements that reduced job execution times by 15% and decreased system downtime by implementing automated recovery mechanisms. Collaborated with internal engineering teams to integrate the Runner seamlessly with other GitHub services, resulting in a more cohesive user experience for millions of developers.

APFM Inc. — New York, USA (Remote) — Senior Full-Stack Engineer - Vendor

November 2021 - August 2022

Designed and implemented a highly efficient CMS (Content Management System) used by over 500 employees, allowing teams to manage vast amounts of content with ease. On the front-end, utilized React to develop dynamic, user-friendly interfaces that improved employee productivity by simplifying navigation and reducing the time spent on content management by 20%. Built responsive, mobile-friendly interfaces, ensuring a seamless user experience across devices. On the back-end, developed scalable APIs using Node.js to manage the platform’s extensive data integration requirements, enabling the system to process high volumes of data from various external sources in real-time. Enhanced data storage and retrieval mechanisms by incorporating MongoDB, improving data access times by 30% and supporting efficient management of large datasets. Focused on optimizing platform performance through regular code reviews, refactoring, and performance tuning, contributing to a 25% increase in system reliability.

Vivify Ideas — Novi Sad, Serbia (Remote) — Full-Stack Engineer

March 2021 - August 2022

Developed multiple web and mobile applications for high-profile clients across fintech, e-commerce, and education sectors. Took ownership of end-to-end development processes, from initial requirement gathering to deployment, ensuring that client expectations were met. Worked closely with senior developers to architect and build both front-end and back-end systems using technologies like React.js, Flask, Vue.js, and Laravel. On the front-end, created responsive and accessible user interfaces, focusing on delivering smooth user experiences across various platforms. On the back-end, developed APIs that supported complex business logic and integrated with third-party services. Contributed to the design and implementation of automated testing frameworks, improving code quality and reducing bugs by 30%. Worked on several international projects, providing custom solutions to meet each client’s specific requirements, often within tight deadlines.

Worked as a full-time freelancer, delivering custom web solutions for clients from various industries, including e-commerce, real estate, and digital marketing. Translated client needs into fully functional web applications using React for the front-end and Node.js for the back-end, ensuring that each solution was tailored to the client’s specific business goals. Developed web scraping APIs using Flask to automate tasks such as data collection from competitor websites, significantly improving clients' market analysis capabilities. Collaborated with remote teams across time zones, managing project scopes and deadlines effectively. Delivered projects that improved client efficiency.

Schneider Electric DMS— Novi Sad, Serbia — Software Engineer

March 2017 - February 2020

Contributed to the development of SCADA (Supervisory Control and Data Acquisition) systems used to manage critical infrastructure in the energy sector. Focused on developing and maintaining robust, real-time monitoring and control systems that ensured the reliable operation of industrial processes. Collaborated with cross-functional teams to design and implement core system modules, optimizing performance for large-scale deployments. Improved workflow efficiency by streamlining data communication between distributed control systems, ensuring minimal latency and high accuracy in data reporting. Worked on the integration of SCADA systems with third-party devices, enhancing interoperability and expanding system capabilities. Conducted performance tests and troubleshooting for large-scale energy distribution systems, identifying and resolving system bottlenecks to improve overall system uptime.